mes/mlibc.c

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/* -*-comment-start: "//";comment-end:""-*-
* Mes --- Maxwell Equations of Software
* Copyright © 2016,2017 Jan Nieuwenhuizen <janneke@gnu.org>
*
* This file is part of Mes.
*
* Mes is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or (at
* your option) any later version.
*
* Mes is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Mes. If not, see <http://www.gnu.org/licenses/>.
*/
#if __GNUC__
int g_stdin = 0;
typedef long size_t;
void *malloc (size_t i);
int open (char const *s, int mode);
int read (int fd, void* buf, size_t n);
void write (int fd, char const* s, int n);
void
exit (int code)
{
asm (
"movl %0,%%ebx\n\t"
"movl $1,%%eax\n\t"
"int $0x80"
: // no outputs "=" (r)
: "" (code)
);
// not reached
exit (0);
}
void
assert_fail (char* s)
{
eputs ("assert fail: ");
eputs (s);
eputs ("\n");
*((int*)0) = 0;
}
#define assert(x) ((x) ? (void)0 : assert_fail (#x))
char const*
getenv (char const* p)
{
return 0;
}
int
read (int fd, void* buf, size_t n)
{
int r;
//syscall (SYS_write, fd, s, n));
asm (
"movl %1,%%ebx\n\t"
"movl %2,%%ecx\n\t"
"movl %3,%%edx\n\t"
"movl $0x3,%%eax\n\t"
"int $0x80\n\t"
"mov %%eax,%0\n\t"
: "=r" (r)
: "" (fd), "" (buf), "" (n)
: "eax", "ebx", "ecx", "edx"
);
return r;
}
int
open (char const *s, int mode)
{
int r;
//syscall (SYS_open, mode));
asm (
"mov %1,%%ebx\n\t"
"mov %2,%%ecx\n\t"
"mov $0x5,%%eax\n\t"
"int $0x80\n\t"
"mov %%eax,%0\n\t"
: "=r" (r)
: "" (s), "" (mode)
: "eax", "ebx", "ecx"
);
return r;
}
int puts (char const*);
char const* itoa (int);
int ungetc_char = -1;
int
getchar ()
{
char c;
int i;
if (ungetc_char == -1)
{
int r = read (g_stdin, &c, 1);
if (r < 1) return -1;
i = c;
}
else
{
i = ungetc_char;
ungetc_char = -1;
}
if (i < 0) i += 256;
return i;
}
int
ungetc (int c, int fd)
{
assert (ungetc_char == -1);
ungetc_char = c;
return c;
}
void
write (int fd, char const* s, int n)
{
int r;
//syscall (SYS_write, fd, s, n));
asm (
"mov %0,%%ebx\n\t"
"mov %1,%%ecx\n\t"
"mov %2,%%edx\n\t"
"mov $0x4, %%eax\n\t"
"int $0x80\n\t"
: // no outputs "=" (r)
: "" (fd), "" (s), "" (n)
: "eax", "ebx", "ecx", "edx"
);
}
int
putchar (int c)
{
//write (STDOUT, s, strlen (s));
//int i = write (STDOUT, s, strlen (s));
write (1, (char*)&c, 1);
return 0;
}
void *
malloc (size_t size)
{
int *n;
int len = size + sizeof (size);
//n = mmap (0, len, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, 0, 0 );
*n = len;
return (void*)(n+1);
}
void
free (void *p)
{
int *n = (int*)p-1;
//munmap ((void*)p, *n);
}
#define EOF -1
#define STDIN 0
#define STDOUT 1
#define STDERR 2
size_t
strlen (char const* s)
{
int i = 0;
while (s[i]) i++;
return i;
}
int
strcmp (char const* a, char const* b)
{
while (*a && *b && *a == *b) {a++;b++;}
return *a - *b;
}
int
eputs (char const* s)
{
//int i = write (STDERR, s, strlen (s));
int i = strlen (s);
write (2, s, i);
return 0;
}
int
fputs (char const* s, int fd)
{
//int i = write (fd, s, strlen (s));
int i = strlen (s);
write (fd, s, i);
return 0;
}
int
puts (char const* s)
{
//int i = write (STDOUT, s, strlen (s));
int i = strlen (s);
write (1, s, i);
return 0;
}
char itoa_buf[10];
char const*
itoa (int x)
{
//static char itoa_buf[10];
//char *p = buf+9;
char *p = itoa_buf;
p += 9;
*p-- = 0;
//int sign = x < 0;
int sign;
sign = x < 0;
if (sign)
x = -x;
do
{
*p-- = '0' + (x % 10);
x = x / 10;
} while (x);
if (sign)
*p-- = '-';
return p+1;
}
int
isdigit (char c)
{
return (c>='0') && (c<='9');
}
#endif